The use of these pharmaceutical compositions according to the invention is directed particularly against preneoplastic lesions which have not or not yet manifested themselves clinically or morphologically and which are causally connected with an exposure to or treatment by physical and/or chemical agents in mammals, particularly humans, and may result in malignant degeneration.
As far as is known, cytokines have hitherto been used systemically only for treating manifest cancers or tumours, i.e. after neoplastic transformation of certain types of cells or tissue has taken place, and in some cases an effect has been shown in vitro and in vivo (Berry, S. F. et al., J. Immunol. 135, 1165-1171, 1985; Ruddle N. H., Immunol. today 8, 129, 1987; Bentler B. & Cerami, A., New Engl. J. Medicine 316, 379-382, 1987).
It is also known to use interferon-containing gels either locally or topically for treating existing precancerous changes in external tissue areas such as the skin or mucous membranes (WO 83/01198). Systemic treatment is regarded as being ineffective or, on account of the possibility of an excessively high dosage, disadvantageous or harmful. The teaching of WO 83/01198 is taken up by U.S. Pat. No. 4,605,555, which also discloses the exclusively external, i.e. topical or local administration of interferon-containing gels, ointments, pastes, liquids or sprays.
Since the fight against existing cancers, even using the more modern methods, has not hitherto shown the levels of success hoped for, particular significance must be accorded to the treatment of preneoplastic lesions, and particularly the prevention or interruption of the process of neoplastic transformation.